Reduce to lowest terms: $- \dfrac{2}{9} \div \dfrac{9}{8} = {?}$
Solution: Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. The reciprocal of $ \dfrac{9}{8}$ is $ \dfrac{8}{9}$ Therefore: $ - \dfrac{2}{9} \div \dfrac{9}{8} = - \dfrac{2}{9} \times \dfrac{8}{9} $ $ \phantom{- \dfrac{2}{9} \times \dfrac{8}{9}} = \dfrac{-2 \times 8}{9 \times 9} $ $ \phantom{- \dfrac{2}{9} \times \dfrac{8}{9}} = \dfrac{-16}{81} $